Conventional magnetic disk drives are information storage devices which utilize at least one rotatable thin film magnetic media disk with concentric data tracks, a read/write transducer for reading and writing data on the various tracks, an air bearing slider for holding the transducer adjacent to the track generally and a flying mode above the media, a suspension for resiliently holding the slider and the transducer over the data tracks, and a positioning actuator connected to the suspension for moving the transducer across the medium to desired data track and maintaining the transducer over the data track during a read or a write operation.
The recording density of a thin film magnetic disk drive is limited by the distance between the transducer and the magnetic media. One goal of thin film hard disk drive design has been to provide a slider which will "fly" as closely as possible to the magnetic medium while avoiding physical impact with the medium. Small spacings, or "fly heights," are desired so that the transducer can distinguish between the magnetic fields emanating from closely spaced regions on the disk.
In addition to achieving a small average spacing between the thin film disk and the transducer, it is also critical that the slider fly at a relatively constant height. The large variety of conditions the transducers experience during the normal operation of a disk drive can make constancy of fly height anything but a given. As the flying height is not constant, the data transfer between the transducer and the recording medium may be adversely affected.
To ensure regular fly height, both thin film disks and sliders are often coated or finished with compositions which will lubricate the respective surfaces or provide a hard and smooth surface. Thin film magnetic disks are usually covered with a lubricant. Lubricants which may be used to coat thin film magnetic recording disks include Z-DOL, AM-2001, and Z-DIAC all available from Montedison of Italy, the Demnum series of lubricants available from, Daikin of Japan, including Demnum-SA, -SH, and -SP, and Krytox brand lubricant from DuPont.
Lubricants are generally chosen to prevent "sticktion" events or fluid friction events between the slider air bearing surface and the surface of the thin film magnetic disk. Lubricants may also be used to preclude or protect the surface of the thin film magnetic disk from direct contact with contaminants. Generally, lubricants are chosen for a particular application empirically based upon the best performance in the given application. For example, Pedrotty, U.S. Pat. No. 4,268,556 discloses fluorinated telechelic polyether polymers which may be used as a lubricant for particulate magnetic recording disks. The Pedrotty particulate disks have a surface which comprises particles of iron dispersed in a epoxy binder. The surface of the particulate disk is very rough which prohibits the head from flying close to the disk.
The disk drive environment can frustrate if not completely undermine the activity of the lubricant. For example, the presence of aluminum within the alloys used to fabricate thin film magnetic disks can lead to lubricant degradation and destabilization. Lubricant breakdown is thought to occur by acid/base reactions as well as electron transfer events. In turn, the breakdown of the lubricant undermines the protective function this film is intended to serve as a coating of a thin film magnetic disk.
One solution proposed has been the use of hexa-phenoxy-cyclo-triphosphazene which is commercially available as XIP from Minnesota Mining and Manufacturing Co. However, this lubricant is expensive and somewhat inefficient as there is a need to blend one or more solutions before application of the lubricant to the thin film magnetic disk.
Accordingly, there is a need for processes and compositions which may be used to stabilize lubricant films which are applied to thin film magnetic disks.